HIV Diagnosis: New
Tests, New Algorithms
and a New Focus
Berry Bennett, MPH
Retrovirology Section Chief
FL Bureau of Public Health Laboratories,
FDOH
berry_bennett@doh.state.fl.us
Disclosures of Financial Relationships
This speaker has no significant financial
relationships with commercial entities to
disclose.
This speaker will discuss off-label use or
investigational product during the program.
This slide set has been peer-reviewed to ensure that there are no
conflicts of interest represented in the presentation.
Common HIV-1 or HIV-1/2 Diagnostic
Algorithm
1989……………………….
 The Public Health Service
recommends that no positive
test results be given to
clients/patients until a
screening test has been
repeatedly reactive (i.e.,
greater than or equal to two
tests) on the same specimen
and a supplemental, more
specific test such as the
Western blot has been used to
validate those results
Common HIV-1 or HIV-1/2 POC Rapid
Test Algorithm
1998………………..
 Healthcare providers should
provide preliminary positive
test results before
confirmatory results are
available in situations where
tested persons benefit.
 When additional rapid tests
become available for use in the
United States, the PHS will reevaluate algorithms using
specific combinations of two
or more rapid tests for
screening and confirming HIV
infection.
Challenges with the 1989 & 1998
Diagnostic Algorithms
• Antibody tests do not detect infection in ~10% of infected
persons at highest risk of transmission1,2
• Western blot (WB) confirmation is less sensitive during
early infection than many widely used screening tests
• Assays were FDA-approved as screening or supplemental
tests in the confirmatory process, not as part of “multi-test
algorithm”.
• WB and Immunofluorescent Assay (IFA) supplemental
assays cannot differentiate HIV-1 from HIV-2 infections.
1) Patel, et.al. Arch Intern Med 2010; 170:66-74
2) Stekler et.al. Clin Infect Diseases 2009; 49:444-53
HIV-2 Cases Confirmed at CDC
2008-2010
*Data courtesy of Dr. Michele Owen, CDC, from CDC’s HIV Diagnostic Laboratory, 2008-2010.
Detection of HIV by Diagnostic
Tests
Symptoms
p24 Antigen
HIV RNA
HIV Enzyme
Immune Assay (EIA)*
Western blot
0
1
2
3
4
5
6
7
8
9
Weeks Since Infection
Modified from After Fiebig et
al, AIDS 2003; 17(13):1871-9
*4th generation, Ag/Ab Combo EIA
*3rd generation, IgM-sensitive EIA
*2nd generation EIA
*viral lysate EIA
10
Characteristics & Performance of
4th Generation Immunoassays
• Simultaneous qualitative detection of HIV-1 p24 antigen and
antibodies to HIV-1 (Groups M and O) and HIV-2 in human serum or
plasma.
•
Abbott Architect HIV Ag/Ab
Combo chemiluminescent
assay (CIA), June 2010.
Package insert sensitivity 100%
(95% CI = 94.31 - 100%).
Package Insert specificity 99.77%
(95% CI = 99.62 – 99.88%)
•
BioRad HIV Combo Ag/Ab EIA,
July 2011.
Package Insert sensitivity 100%
(95% CI = 99.7 – 100%).
Package Insert specificity 99.87%
(95% CI = 99.76 – 99.93%).
Process for Developing New HIV
Testing Algorithms for the U.S.
 Association of Public Health Laboratories (APHL)/CDC HIV Steering Committee (2006)
 Algorithm Workgroups [Point of contact (POC) and Laboratory]
Goal = Develop multiple acceptable HIV testing
algorithms, i.e., a menu of options
 APHL & National Alliance of State and Territorial AIDS Directors (NASTAD) Public
Health Surveys
 2007 HIV Diagnostics Conference (December 5-7, Atlanta)
 Preparation of the Status Report, released April 2009 at
www.aphl.org/hiv/statusreport
 Status Report promotion at national conferences
 2010 HIV Diagnostics Conference (March 24-26, Orlando)
 Release of the Clinical and Laboratory Standards Institute (CLSI) Guidelines1,
July 2011
 CDC Dear Colleague letter to Surveillance Coordinators, Nov. 18, 2011
 Each state must examine their case reporting and Ryan White eligibility criteria
 Ongoing data gathering: retrospective and prospective
 CDC Interim Guidance anticipated by mid-2012
 2012 HIV Diagnostic Conference set for Dec. 12-14, 2012
1 Final CDC Recommendations to follow
Criteria for Laboratory Testing and Diagnosis of Human Immunodeficiency Virus Infection: Approved Guidelines. Clinical and
Laboratory Standards Institute, M53-A.
CDC Dear Colleague Letter to
Surveillance Coordinators – Nov. 18, 2011
“Supplemental HIV antibody tests”
need not be limited to Western Blot
or IFA. Other antibody tests are
acceptable as supplemental tests,
including some that might
alternatively be used as initial
screening tests, provided that the
screening and supplemental tests
are used together as parts of an
algorithm.
Characteristics of the Proposed HIV
Diagnostic Algorithm
• Detect acute as well as established HIV
infections
• Differentiate HIV-1 from HIV-2
• Get timely results to facilitate initiation of care more same day reporting
• Eliminate indeterminate and inconclusive results
whenever possible
APHL/CDC HIV-1/2 Diagnostic
Algorithm Template
4th Generation Immunoassays
Options for Test A*
• Simultaneous qualitative detection of HIV-1 p24 antigen
and antibodies to HIV-1 (Groups M and O) and HIV-2 in
human serum or plasma.
• Abbott Architect HIV Ag/Ab
Combo chemiluminescent
assay (CIA), June 2010.
• BioRad HIV Combo Ag/Ab
EIA, July 2011.
* 3rd generation IgM sensitive Ab assay is acceptable
Possible HIV-1/HIV-2 Differentiation
Immunoassays
Options for Test B
Non-FDA-approved
FDA-approved
Serum Control
1
2
3
4
5
gp36
gp160
gp120
gp41
gp24
Peptide HIV-2 gp36
Recombinant HIV-1 gp41
Peptide HIV-1 gp41
HIV-1 Nucleic Acid Amplification
Tests (NAAT)
Options for Test C
• Only one HIV-1 RNA test is FDA-approved for use as an aid in
the diagnosis of HIV-1 infection
– APTIMA® HIV-1 RNA Qualitative Assay (Gen-Probe)
– Approved for use with plasma and serum
– Result is ‘RNA Detected/Not Detected’
• HIV-1 RNA Viral Load assays are FDA-approved for patient
monitoring, i.e. assess prognosis, monitor effects of therapy
– Not intended as a diagnostic test to confirm the presence of HIV-1
infection
– Approved for use with plasma only
– Lab would need to validate viral load test for use as a diagnostic test
and for use with serum
FBPHL – Jax. 10,000 Test Mark
• 4/16/12 – 5/21/12
• 4th generation Abbott HIV-1/2 Ag/Ab Combo Performance;
sensitivity = 100% (161/161)
specificity = 99.8% (9819/9839) [PI claim 99.77% (99.62-99.88%)]
• New algorithm performance;
sensitivity = 100% (161/161)
specificity = 99.99% (9838/9839)
PPV = 99.4% (161/162)
• No HIV-1 acute infections (AHIs) (algorithm defined) detected in the first
10,000 diagnostic tests. (2 AHIs detected in ~46,000 screens)
• No HIV-2 cases detected.
HIV-1 Acute Infection Case Study
• 19 y/o MSM from Broward County Health Department
• Last HIV-negative test 8/5/12 (rapid), client informed that his partner “X” was
recently diagnosed HIV-1 positive on 8/3/12
• 1st blood draw on 8/15/12 and processed through the Florida Bureau of Public
Health Laboratories (BPHL) new HIV Diagnostic Algorithm (4th gen CIA
repeatedly reactive, Supplemental immunoassay [IA] nonreactive, HIV-1 nucleic
acid amplification test [NAAT] positive). Reported as AHI on 8/24/12.
• Subsequent blood draw on 8/24/12, seroconversion confirmed on 8/27/12.
• At post-test (8/24/12) client admits to MSM risk with partner “X” between
7/25/12 and 8/7/12. The window period of detection for the 4th gen CIA on this
case is estimated to be between 8 and 21 days.
• HIV-1 baseline viral load performed 8/30/12 by Versant bDNA = 266,784 RNA
copies/ml.
Pregnancy and the New
4th Generation Immunoassays
•
•
•
Abbott 4th Generation CIA specificity = 100% (448/448 pregnant females at increased risk
of HIV infection) compared to 98.9% (448/453) specificity for an HIV-1/2/O antibody assay.
– Abbott HIV-1/2 Combo package insert
BioRad 4th Generation EIA specificity = 99.89% (998/999) – BioRad Combo Ag/Ab EIA
package insert
Weslowski L, Delaney, K, et.al. “Rapid HIV Tests as Supplemental Tests in Pregnant
Women and Others with Reactive IgM-Sensitive Immunoassay Results and
Unconfirmed Western Blots” – International AIDS Conference July 2012
Rapid HIV Test Rapid Test Specificity Pregnant Women (n=838) (NAAT negative)
Clearview®
99.88% (99.34%-99.97%)
Multispot
99.16% (98.29%-99.66%)
OraQuick®
99.76% (99.14%-99.97%)
Uni-Gold™
99.76% (99.14%-99.97%)
•
•
Conclusion: The proportion of false-positive results was higher for non-pregnant persons
than pregnant women (p<0.05).
If one suspects a false-positive initial rapid test due to pregnancy, consider; 1) dual
orthogonal rapid or lab-based algorithm, 2) Qualitative NAAT or 3) collect a subsequent
blood specimen
Proposed HIV Point of Care Algorithm
Two Rapid Tests (A1/A2) Performed in Sequence on Blood or
Oral Fluid (A1 and A2 must be different rapid tests)
A1
[HIV-1 or HIV-1/2 rapid test (Blood or oral fluid)]
A1+
A2
A1Negative for HIV-1
and HIV-2 antibodies*
[HIV-1 or HIV 1/2 rapid test from a
different manufacturer (blood)]
A1+ A2+
Presumptive positive for
HIV-1 or HIV-2
antibodies; requires
medical follow-up for
further evaluation and
testing
A1+ A2Inconclusive rapid test
result;
requires additional testing
*If using an HIV-1 only rapid test, Negative for HIV-1 antibodies only
FDA Approved HIV Rapid Tests
Product
Manufacturer
Analyte
Specimen
Type
Sensitivity
Specificity
FDA
Approval
Uni-Gold
Recombigen™
HIV
Trinity Biotech
www.trinityusa.co
m
HIV-1
Whole blood,
Serum, Plasma
100%
99.7%
Dec. 2003
OraQuick
ADVANCE®
HIV-1/2
Orasure
Technologies
www.orasure.com
HIV-1
HIV-2
Whole blood,
Oral fluid,
Plasma
99.6% BL
99.3% OF
June 2004
*91.7% OF
100% BL
99.8% OF
99.9% plasma
*99.98% OF
OTC 7/2012
Multispot
HIV1/HIV2
BioRad Labs
www.bio-rad.com
HIV-1
HIV-2
Serum, Plasma
100%
99.9%
Nov. 2004
Clearview®
HIV 1/2 STATPAK® &
Complete
HIV 1/2
Inverness Med.
www.invernessme
dicalpd.com
HIV-1
HIV-2
Whole blood,
Serum, Plasma
99.7%
99.9%
May 2006
INSTI™ HIV-1
bioLytical Labs
www.biolytical.com
HIV-1
Whole blood,
Plasma
99.8%
99.5%
Nov. 2010
Reveal® G3
Rapid HIV-1
MedMira
www.revealhiv.com
HIV-1
Serum, Plasma
99.8%
99.1% serum
98.6% plasma
Oct. 2006
* FDA. Summary of Safety and Effectiveness PMA # BP120001, 7/3/2012
FDA Approved HIV Rapid Tests
OTC Application
Rapid Tests Pending FDA Approval
Alternative Algorithms
• Individual or pooled NAAT on seronegative specimens (reflex
testing)
• Traditional algorithm with supplemental NAAT option instead of
Western Blot.
• Algorithms for oral fluid and dried fluid spot (DFS) specimens.
• “Bridge algorithms” (POC – laboratory – clinical management)
HIV Testing Algorithm Information
•
HIV Testing Algorithms: A Status Report (5/2009)
http://www.aphl.org/hiv/statusreport
•
2010 HIV Diagnostics Conference: http://www.hivtestingconference.org
•
CLSI M53-A, Criteria for Laboratory Testing and Diagnosis of HIV-1 Infection, June
2011. (Includes algorithms utilizing assays available outside the US as well as those
FDA approved)
•
Original papers and review articles assembled in Special Supplement of J Clin Virol,
2011
•
Updated CDC recommendations anticipated 2012.
Thank you & Questions??